Greetings, Number plate holder ?, I thought you said you couldn't fault it
Seriously though, seek out a local wreckers yard that has one, as it'll be the best source of cheap spares you'll get, especially if you can put a 'package' of things together. Failing that, eBay usually has everything you'll want and nowadays comes with guarantees .
If it's the same arrangement as mine (1.4 with lights above the number plate) the screws will be corroded in their sockets and perhaps impossible to remove, so be careful when getting the old light units off.
Mine is an Active Air (although the "Air" part doesn't work) ans has the later (2004) rear lamps (which look a bit saucier in my opinion)... but still, yours is pretty tidy.
How many miles has it done? I'll tell you what'll go wrong with it...